發(fā)布時(shí)間：2018-02-11 21:41

  本文關(guān)鍵詞： 統(tǒng)一強(qiáng)度理論 鋼管RPC 軸壓承載力 界面粘結(jié)性能 沖擊荷載 SHPB數(shù)值模擬　出處：《長安大學(xué)》2014年博士論文　論文類型：學(xué)位論文

【摘要】：活性粉末混凝土(簡稱RPC)作為綠色高性能混凝土具有超高強(qiáng)度、高韌性、耐久性好、體積穩(wěn)定性優(yōu)良的特點(diǎn)，是混凝土未來的發(fā)展方向。將其應(yīng)用于組合結(jié)構(gòu)形成鋼管活性粉末混凝土結(jié)構(gòu)構(gòu)件，對(duì)其研究具有重要的理論意義和工程應(yīng)用價(jià)值。本文研究了不同截面形式鋼管RPC的軸壓性能、粘結(jié)滑移與界面粘結(jié)損傷性能、尺寸效應(yīng)模型和鋼管RPC的抗沖擊性能。主要的研究工作和創(chuàng)新成果如下： (1)以統(tǒng)一強(qiáng)度理論和厚壁圓筒理論為基礎(chǔ)，推導(dǎo)了圓形、方形和圓端形截面鋼管RPC軸壓短柱的承載力計(jì)算公式。運(yùn)用勢能駐值原理，考慮鋼管和RPC之間的套箍效應(yīng)，推導(dǎo)出鋼管RPC柱在軸向壓力作用下組合彈性模量的計(jì)算式，并進(jìn)一步分析鋼管RPC柱的組合軸壓剛度。采用粘結(jié)強(qiáng)度和割線模量定義了界面粘結(jié)損傷變量，建立了一種基于損傷理論的鋼管與RPC的界面粘結(jié)損傷模型，揭示了鋼管RPC界面粘結(jié)的損傷機(jī)理。 (2)基于統(tǒng)一屈服準(zhǔn)則和應(yīng)變梯度塑性理論，推導(dǎo)考慮尺寸效應(yīng)的厚壁圓筒塑性極限解，得到考慮尺寸效應(yīng)的外鋼管的縱向抗壓強(qiáng)度，研究了鋼管RPC的尺寸效應(yīng)規(guī)律及不同變形條件下尺寸效應(yīng)的作用機(jī)理。采用Weibull統(tǒng)計(jì)尺寸效應(yīng)模型對(duì)核心RPC的抗壓強(qiáng)度進(jìn)行修正，對(duì)外鋼管采用考慮尺寸效應(yīng)的厚壁圓筒理論，從而對(duì)不同截面形式的鋼管RPC軸壓短柱提出了考慮界面粘結(jié)性能和尺寸效應(yīng)的軸壓承載力計(jì)算方法，，并探討了強(qiáng)度理論參數(shù)、套箍指標(biāo)和活性粉末混凝土強(qiáng)度對(duì)承載力的影響特性。 (3)采用三段線近似模擬鋼管RPC的粘結(jié)滑移本構(gòu)模型，以便于進(jìn)行ANSYS數(shù)值模擬時(shí)彈簧單元的施加。對(duì)于鋼管RPC粘結(jié)滑移數(shù)值模擬采用非線性彈簧單元Combination39，分析了該單元的特點(diǎn)以及F D曲線選取的計(jì)算方法。非線性彈簧單元分別模擬了鋼管與活性粉末混凝土之間法向、縱向切向、環(huán)向切向三個(gè)方向的作用。利用ANSYS后處理器得到的不同截面形式鋼管RPC短柱的軸壓承載力和荷載-變形關(guān)系曲線，與文獻(xiàn)中試驗(yàn)曲線吻合較好，探討了RPC軸壓強(qiáng)度、套箍系數(shù)和軸壓剛度比對(duì)鋼管RPC軸壓短柱極限承載力的影響。 (4)采用LS-DYNA軟件對(duì)RPC短柱和鋼管RPC短柱進(jìn)行分離式霍普金森壓桿(簡稱SHPB)有限元數(shù)值模擬。數(shù)值分析得到的應(yīng)力波的波形圖、構(gòu)件的軸向應(yīng)力時(shí)程和軸向應(yīng)變時(shí)程、重構(gòu)的應(yīng)力應(yīng)變曲線均與試驗(yàn)結(jié)果基本一致，證明了有限元模型的合理性�；贑EB公式和Malver公式推導(dǎo)鋼管RPC試件的動(dòng)態(tài)增長因子計(jì)算表達(dá)式，給出了三波法和兩波法計(jì)算試件應(yīng)變、應(yīng)力和應(yīng)變率的基本公式。研究了沖擊荷載作用下RPC應(yīng)變率強(qiáng)化的特性、試件破壞過程以及動(dòng)態(tài)增長因子的響應(yīng)規(guī)律，探討了活性粉末混凝土強(qiáng)度、鋼管壁厚度、套箍系數(shù)等因素對(duì)鋼管RPC構(gòu)件的抗沖擊性能的影響特性。
[Abstract]:As green high performance concrete, reactive powder concrete (RPC) has the characteristics of super high strength, high toughness, good durability and good volume stability. It is the development direction of concrete in the future. In this paper, the axial compression behavior, bond-slip and interfacial bond damage of steel tube RPC with different cross-section forms are studied. Size effect model and impact resistance of steel tube RPC. The main research and innovative results are as follows:. 1) based on the unified strength theory and the thick wall cylinder theory, the formulas for calculating the bearing capacity of RPC short columns with circular, square and circular end sections are derived. The hoop effect between the steel tube and RPC is considered by using the principle of standing potential energy. The formula of composite elastic modulus of steel tube RPC column under axial pressure is derived, and the combined axial compression stiffness of steel tube RPC column is further analyzed. The interface bond damage variable is defined by bond strength and Secant modulus. A damage model of interface bond between steel tube and RPC is established based on damage theory, and the mechanism of interface bond damage of steel tube RPC is revealed. Based on the unified yield criterion and strain gradient plasticity theory, the plastic limit solution of thick-walled cylinder considering size effect is derived, and the longitudinal compressive strength of outer steel pipe considering size effect is obtained. The size effect law of steel tube RPC and the action mechanism of dimension effect under different deformation conditions are studied. The compressive strength of core RPC is modified by Weibull statistical size effect model, and the thick-walled cylinder theory considering size effect is adopted in external steel pipe. Thus, the calculation method of axial compression capacity of steel tube RPC short columns with different cross-section forms considering the interfacial bond property and size effect is put forward, and the theoretical strength parameters are discussed. The influence of hoop index and reactive powder concrete strength on bearing capacity. The bond-slip constitutive model of steel pipe RPC is simulated by three-segment line approximation. In order to facilitate the application of spring element in ANSYS numerical simulation, the nonlinear spring element combination 39 is used in the numerical simulation of RPC bond-slip of steel pipe. The characteristics of the element and the calculation method of selecting F-D curve are analyzed. The normal direction between the steel tube and the reactive powder concrete was simulated by the element. The axial bearing capacity and load-deformation relation curves of RPC short columns with different cross-section obtained by ANSYS post-processor are in good agreement with the experimental curves in literature. The axial compression strength of RPC is discussed. The influence of hoop coefficient and axial compression stiffness ratio on ultimate bearing capacity of steel tube RPC short columns under axial compression. (4) finite element numerical simulation of split Hopkinson compression bar (SHPB) for RPC short column and RPC tube short column is carried out by using LS-DYNA software. The waveforms of stress wave, axial stress time history and axial strain time history are obtained by numerical analysis. The reconstructed stress-strain curves are basically consistent with the experimental results, which proves the rationality of the finite element model. Based on the CEB formula and the Malver formula, the expression of the dynamic growth factor of the steel tube RPC specimen is derived. The basic formulas for calculating strain, stress and strain rate of specimen by three wave method and two wave method are given. The characteristics of strain rate strengthening of RPC under impact load, the failure process of the specimen and the response law of dynamic growth factor are studied. The effects of the strength of reactive powder concrete (RPC), the thickness of steel tube wall and the hoop coefficient on the impact resistance of steel tube RPC members are discussed.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU398.9;TU317

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本文編號(hào)：1504063